Add Serialization Benchmark (#250)

Introduce benchmarks using a large GraphQL query to measure
parse and pickle serialization performance. These provide a baseline
for comparing serialization approaches in subsequent commits.

Author: corydolphin

tests/benchmarks/test_serialization.py

@@ -0,0 +1,50 @@
+"""Benchmarks for pickle serialization of parsed queries.
+
+This module benchmarks pickle serialization using a large query (~100KB)
+to provide realistic performance numbers for query caching use cases.
+"""
+
+import pickle
+
+from graphql import parse
+
+from ..fixtures import large_query  # noqa: F401
+
+# Parse benchmark
+
+
+def test_parse_large_query(benchmark, large_query):  # noqa: F811
+    """Benchmark parsing large query."""
+    result = benchmark(lambda: parse(large_query, no_location=True))
+    assert result is not None
+
+
+# Pickle benchmarks
+
+
+def test_pickle_large_query_roundtrip(benchmark, large_query):  # noqa: F811
+    """Benchmark pickle roundtrip for large query AST."""
+    document = parse(large_query, no_location=True)
+
+    def roundtrip():
+        encoded = pickle.dumps(document)
+        return pickle.loads(encoded)
+
+    result = benchmark(roundtrip)
+    assert result == document
+
+
+def test_pickle_large_query_encode(benchmark, large_query):  # noqa: F811
+    """Benchmark pickle encoding for large query AST."""
+    document = parse(large_query, no_location=True)
+    result = benchmark(lambda: pickle.dumps(document))
+    assert isinstance(result, bytes)
+
+
+def test_pickle_large_query_decode(benchmark, large_query):  # noqa: F811
+    """Benchmark pickle decoding for large query AST."""
+    document = parse(large_query, no_location=True)
+    encoded = pickle.dumps(document)
+
+    result = benchmark(lambda: pickle.loads(encoded))
+    assert result == document

tests/fixtures/__init__.py

@@ -12,6 +12,7 @@
     "cleanup",
     "kitchen_sink_query",
     "kitchen_sink_sdl",
+    "large_query",
 ]
 
 
@@ -54,3 +55,8 @@ def big_schema_sdl():
 @pytest.fixture(scope="module")
 def big_schema_introspection_result():
     return read_json("github_schema")
+
+
+@pytest.fixture(scope="module")
+def large_query():
+    return read_graphql("large_query")